finish load/save features

7 files changed, 235 insertions, 54 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0adf88f..64afd87 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -134,7 +134,7 @@ dependencies = [
 
 [[package]]
 name = "runes"
-version = "0.1.5"
+version = "0.1.6"
 dependencies = [
  "clap 2.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sdl2 0.31.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/Cargo.toml b/Cargo.toml
index 42bd0e2..8a39686 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "runes"
-version = "0.1.5"
+version = "0.1.6"
 authors = ["Determinant <tederminant@gmail.com>"]
 description = "No-std NES emulator library and minimal emulator written purely in Rust."
 repository = "https://github.com/Determinant/runes"
diff --git a/README.rst b/README.rst
index 7e41122..4e19c9a 100644
--- a/README.rst
+++ b/README.rst
@@ -8,22 +8,23 @@ RuNES
 
 As we know, there have been a ton of NES emulator implementations in various
 kinds of languages (mostly C). All of these emulators come with different
-accuracy and portability. RuNES is an attempt to build a reasonably
-accurate (cycle-level accurate), light-weight and efficient emulation
-core library using Rust. Unlike sprocketnes_ or pinky_, RuNES strives to
-provide with a clean and minimal core library without standard library (i.e.,
-without Box, Rc, Vectors, etc.) that could be compiled and easily ported to
-embedded environments. Of course, a minimal SDL-based GUI is also provided as a
-demonstration of use.
+accuracy and portability. RuNES is an attempt to build a reasonably accurate
+(cycle-level accurate), light-weight and efficient emulation core library using
+Rust. Unlike sprocketnes_ or pinky_, RuNES strives to provide with a clean and
+minimal core library without standard library (i.e., without Box, Rc, Vectors,
+etc.) that could be compiled and easily ported to embedded environments. Of
+course, a minimal but usable SDL-based GUI is also provided as a demonstration
+of use.
 
 Feature
 =======
 
 - Core library with minimal use of the Rust core crate, and zero use of std.
+- Lightweight and clean code base.
 - Support standard 6502 instruction set (unofficial instruction will be
   considered in the future).
-
-- Cycle-level accuracy.
+- Load/save the machine state.
+- Cycle-level accuracy (in-progress).
 
 Guidelines
 ==========
diff --git a/src/bin.rs b/src/bin.rs
index d306fb4..07f8487 100644
--- a/src/bin.rs
+++ b/src/bin.rs
@@ -66,6 +66,22 @@ impl SimpleCart {
                mirror_type: MirrorType) -> Self {
         SimpleCart{chr_rom, prg_rom, sram, mirror_type}
     }
+
+    fn load_vec(vec: &mut Vec<u8>, reader: &mut utils::Read) -> bool {
+        let len = vec.len();
+        match reader.read(vec) {
+            Some(x) => x == len,
+            None => false
+        }
+    }
+
+    fn save_vec(vec: &Vec<u8>, writer: &mut utils::Write) -> bool {
+        let len = vec.len();
+        match writer.write(vec) {
+            Some(x) => x == len,
+            None => false
+        }
+    }
 }
 
 impl Cartridge for SimpleCart {
@@ -100,22 +116,24 @@ impl Cartridge for SimpleCart {
     fn set_mirror_type(&mut self, mt: MirrorType) {self.mirror_type = mt}
 
     fn load(&mut self, reader: &mut utils::Read) -> bool {
-        let len = self.sram.len();
-        (match reader.read(&mut self.sram) {
-            Some(x) => x == len,
-            None => false
-        }) &&
+        self.load_sram(reader) &&
+        SimpleCart::load_vec(&mut self.chr_rom, reader) &&
         utils::load_prefix(&mut self.mirror_type, 0, reader)
     }
 
     fn save(&self, writer: &mut utils::Write) -> bool {
-        let len = self.sram.len();
-        (match writer.write(&self.sram) {
-            Some(x) => x == len,
-            None => false
-        }) &&
+        self.save_sram(writer) &&
+        SimpleCart::save_vec(&self.chr_rom, writer) &&
         utils::save_prefix(&self.mirror_type, 0, writer)
     }
+
+    fn load_sram(&mut self, reader: &mut utils::Read) -> bool {
+        SimpleCart::load_vec(&mut self.sram, reader)
+    }
+
+    fn save_sram(&self, writer: &mut utils::Write) -> bool {
+        SimpleCart::save_vec(&self.sram, writer)
+    }
 }
 
 struct FileIO(File);
@@ -387,39 +405,74 @@ fn print_cpu_trace(cpu: &CPU) {
 }
 
 fn main() {
-    let matches = App::new("RuNES")
-                    .version("0.1.5")
-                    .author("Ted Yin <tederminant@gmail.com>")
-                    .about("A Rust NES emulator")
-                    .arg(Arg::with_name("scale")
-                         .short("x")
-                         .long("scale")
-                         .required(false)
-                         .takes_value(true))
-                    .arg(Arg::with_name("full")
-                         .short("f")
-                         .long("full")
-                         .required(false)
-                         .takes_value(false))
-                    .arg(Arg::with_name("INPUT")
-                         .help("the iNES ROM file")
-                         .required(true)
-                         .index(1))
-                    .arg(Arg::with_name("load")
-                         .short("l")
-                         .long("load")
-                         .required(false)
-                         .takes_value(true))
-                    .get_matches();
+    let matches =
+        App::new("RuNES")
+            .version("0.1")
+            .author("Ted Yin <tederminant@gmail.com>")
+            .about("A Rust NES emulator")
+            .arg(Arg::with_name("scale")
+                 .short("x")
+                 .long("scale")
+                 .help("Set pixel scaling factor (3 by default)")
+                 .required(false)
+                 .takes_value(true))
+            .arg(Arg::with_name("full")
+                 .help("Enable the entire PPU rendering area")
+                 .short("f")
+                 .long("full")
+                 .required(false)
+                 .takes_value(false))
+            .arg(Arg::with_name("INPUT")
+                 .help("iNES ROM file")
+                 .required(true)
+                 .index(1))
+            .arg(Arg::with_name("load")
+                 .help("Load from specified machine state file")
+                 .short("l")
+                 .long("load")
+                 .required(false)
+                 .takes_value(true))
+            .arg(Arg::with_name("save")
+                 .help("Save to specified machine state file when exit")
+                 .short("s")
+                 .long("save")
+                 .required(false)
+                 .takes_value(true))
+            .arg(Arg::with_name("load-sram")
+                 .help("Load from specified sram file")
+                 .short("L")
+                 .long("load-sram")
+                 .required(false)
+                 .takes_value(true))
+            .arg(Arg::with_name("save-sram")
+                 .help("Save to specified sram file when exit")
+                 .short("S")
+                 .long("save-sram")
+                 .required(false)
+                 .takes_value(true))
+            .arg(Arg::with_name("no-state")
+                 .help("Power up the emulator with initial state")
+                 .short("n")
+                 .long("no-state")
+                 .required(false)
+                 .takes_value(false))
+            .get_matches();
 
     let scale = std::cmp::min(8,
                     std::cmp::max(1,
                         value_t!(matches, "scale", u32).unwrap_or(3)));
     let full = matches.is_present("full");
 
-    /* load and parse iNES file */
     let fname = matches.value_of("INPUT").unwrap();
-    let lname = matches.value_of("load");
+    let load_state_name = matches.value_of("load");
+    let save_state_name = matches.value_of("save");
+    let save_sram_name = matches.value_of("save-sram");
+    let load_sram_name = matches.value_of("load-sram");
+    let default_state_name = fname.to_string() + ".runes";
+    let default_sram_name = fname.to_string() + ".runes_sram";
+    let no_state = matches.is_present("no-state");
+
+    /* load and parse iNES file */
     let mut file = File::open(fname).unwrap();
     let mut rheader = [0; 16];
     file.read(&mut rheader[..]).unwrap();
@@ -493,19 +546,38 @@ fn main() {
     let mut apu = APU::new(&mut spkr);
     let cpu_ptr = &mut cpu as *mut CPU;
     cpu.mem.bus.attach(cpu_ptr, &mut ppu, &mut apu);
-    match lname {
-        Some(s) => {
-            let mut file = FileIO(File::open(s).unwrap());
+    let load_state = !no_state && match match load_state_name {
+        Some(s) => Some(File::open(s).unwrap()),
+        None => match File::open(&default_state_name) {
+            Ok(file) => Some(file),
+            Err(_) => None
+        }
+    } {
+        Some(f) => {
+            let mut file = FileIO(f);
             cpu.load(&mut file);
             ppu.load(&mut file);
             apu.load(&mut file);
             mapper.get_mut().load(&mut file);
-            debug_assert!(cpu.cycle == 0);
+            true
         },
-        None => {
-            cpu.powerup()
+        None => false
+    };
+
+    if !load_state {
+        if let Some(f) = match load_sram_name {
+            Some(s) => Some(File::open(s).unwrap()),
+            None => match File::open(&default_sram_name) {
+                Ok(file) => Some(file),
+                Err(_) => None
+            }
+        } {
+            let mut file = FileIO(f);
+            mapper.get_mut().get_cart_mut().load_sram(&mut file);
         }
+        cpu.powerup()
     }
+
     device.resume();
     loop {
         /* consume the leftover cycles from the last instruction */
@@ -514,12 +586,22 @@ fn main() {
         }
         if exit_flag.get() {
             {
-                let mut file = FileIO(File::create("t.dat").unwrap());
+                let mut file = FileIO(File::create(match save_state_name {
+                    Some(s) => s.to_string(),
+                    None => default_state_name
+                }).unwrap());
                 cpu.save(&mut file);
                 ppu.save(&mut file);
                 apu.save(&mut file);
                 mapper.save(&mut file);
             }
+            {
+                let mut file = FileIO(File::create(match save_sram_name {
+                    Some(s) => s.to_string(),
+                    None => default_sram_name
+                }).unwrap());
+                mapper.get_cart().save_sram(&mut file);
+            }
             exit(0);
         }
         //print_cpu_trace(&cpu);
diff --git a/src/cartridge.rs b/src/cartridge.rs
index ca9c31e..29cfbd7 100644
--- a/src/cartridge.rs
+++ b/src/cartridge.rs
@@ -24,4 +24,6 @@ pub trait Cartridge {
     #[inline(always)] fn set_mirror_type(&mut self, mt: MirrorType);
     fn load(&mut self, reader: &mut Read) -> bool;
     fn save(&self, writer: &mut Write) -> bool;
+    fn load_sram(&mut self, reader: &mut Read) -> bool;
+    fn save_sram(&self, writer: &mut Write) -> bool;
 }
diff --git a/src/mapper.rs b/src/mapper.rs
index 3d72189..8a6c261 100644
--- a/src/mapper.rs
+++ b/src/mapper.rs
@@ -7,6 +7,7 @@ use utils::{Read, Write, load_prefix, save_prefix};
 
 pub trait Mapper : VMem {
     fn get_cart(&self) -> &Cartridge;
+    fn get_cart_mut(&mut self) -> &mut Cartridge;
     fn tick(&mut self, _bus: &CPUBus) {}
     fn load(&mut self, reader: &mut Read) -> bool;
     fn save(&self, writer: &mut Write) -> bool;
@@ -35,6 +36,7 @@ impl<'a> core::ops::Deref for RefMapper<'a> {
     }
 }
 
+#[repr(C)]
 pub struct Mapper1<'a, C> where C: Cartridge {
     cart: C,
     prg_banks: [&'a [u8]; 2],
@@ -177,6 +179,7 @@ impl<'a, C> Mapper1<'a, C> where C: Cartridge {
 
 impl<'a, C> Mapper for Mapper1<'a, C> where C: Cartridge {
     fn get_cart(&self) -> &Cartridge {&self.cart}
+    fn get_cart_mut(&mut self) -> &mut Cartridge {&mut self.cart}
 
     fn load(&mut self, reader: &mut Read) -> bool {
         for v in self.prg_banks.iter_mut() {
@@ -215,6 +218,7 @@ impl<'a, C> Mapper for Mapper1<'a, C> where C: Cartridge {
     }
 }
 
+#[repr(C)]
 pub struct Mapper2<'a, C> where C: Cartridge {
     cart: C,
     prg_banks: [&'a [u8]; 2],
@@ -282,6 +286,7 @@ impl<'a, C> Mapper2<'a, C> where C: Cartridge {
 
 impl<'a, C> Mapper for Mapper2<'a, C> where C: Cartridge {
     fn get_cart(&self) -> &Cartridge {&self.cart}
+    fn get_cart_mut(&mut self) -> &mut Cartridge {&mut self.cart}
 
     fn load(&mut self, reader: &mut Read) -> bool {
         for v in self.prg_banks.iter_mut() {
@@ -312,6 +317,7 @@ impl<'a, C> Mapper for Mapper2<'a, C> where C: Cartridge {
     }
 }
 
+#[repr(C)]
 pub struct Mapper4<'a, C> where C: Cartridge {
     cart: C,
     prg_banks: [&'a [u8]; 4],
@@ -500,6 +506,8 @@ impl<'a, C> Mapper4<'a, C> where C: Cartridge {
 
 impl<'a, C> Mapper for Mapper4<'a, C> where C: Cartridge {
     fn get_cart(&self) -> &Cartridge {&self.cart}
+    fn get_cart_mut(&mut self) -> &mut Cartridge {&mut self.cart}
+
     fn tick(&mut self, bus: &CPUBus) {
         let ppu = bus.get_ppu();
         if ppu.cycle != 260 {
diff --git a/src/utils.rs b/src/utils.rs
new file mode 100644
index 0000000..ea20ac9
--- /dev/null
+++ b/src/utils.rs
@@ -0,0 +1,88 @@
+use core::intrinsics::transmute;
+use core::mem::size_of;
+use core::slice::{from_raw_parts_mut, from_raw_parts};
+
+pub struct Sampler {
+    freq2: u32,
+    q0: u32,
+    r0: u32,
+    ddl: (u32, u32),
+    cnt: u32,
+    sec_cnt: u32
+}
+
+impl Sampler {
+    pub fn new(freq1: u32, freq2: u32) -> Self {
+        let q0 = freq1 / freq2;
+        let r0 = freq1 - q0 * freq2;
+        Sampler {
+            freq2,
+            q0,
+            r0,
+            ddl: (q0, r0),
+            cnt: 0,
+            sec_cnt: 0
+        }
+    }
+
+    pub fn load(&mut self, reader: &mut Read) -> bool {
+        load_prefix(self, 0, reader)
+    }
+
+    pub fn save(&self, writer: &mut Write) -> bool {
+        save_prefix(self, 0, writer)
+    }
+
+    pub fn tick(&mut self) -> bool {
+        let (q, r) = self.ddl;
+        if self.cnt == q {
+            let nr = r + self.r0;
+            self.ddl = if nr > self.freq2 {
+                (self.q0, nr - self.freq2)
+            } else {
+                (self.q0 - 1, nr)
+            };
+            self.cnt = 0;
+            self.sec_cnt += 1;
+            if self.sec_cnt == self.freq2 {
+                self.sec_cnt = 0
+            }
+            true
+        } else {
+            self.cnt += 1;
+            false
+        }
+    }
+}
+
+pub trait Read {
+    fn read(&mut self, buf: &mut [u8]) -> Option<usize>;
+}
+
+pub trait Write {
+    fn write(&mut self, buf: &[u8]) -> Option<usize>;
+}
+
+pub fn load_prefix<T>(obj: &mut T, ignored: usize, reader: &mut Read) -> bool {
+    let len = size_of::<T>() - ignored;
+    match reader.read(unsafe {
+        from_raw_parts_mut(
+            transmute::<*mut T, *mut u8>(obj as *mut T),
+            len
+    )}) {
+        Some(x) => x == len,
+        None => false
+    }
+}
+
+pub fn save_prefix<T>(obj: &T, ignored: usize, writer: &mut Write) -> bool {
+    let len = size_of::<T>() - ignored;
+    match writer.write(unsafe {
+        from_raw_parts(
+            transmute::<*const T, *const u8>(obj as *const T),
+            len
+            )}) {
+        Some(x) => x == len,
+        None => false
+    }
+}